Aluminum has been implicated in neurological and aging disorders, including Alzheimer's disease and dialysis dementia. Previous trace analysis studies were subject to interferences and contamination, and lacked elemental specificity, sensitivity, and isotopic information. Resonance ionization spectroscopy (RIS), which utilizes laser atom counting techniques, offers the potential to overcome these disadvantages and to probe deeply the mechanistic role of aluminum in neurobiology. Specific aims are to: 1) develop simplified chemical separation and atomization techniques for aluminum; 2) develop resonance ionization schemes for aluminum; 3) demonstrate the feasibility of aluminum determinations in biological matrices; 4) illustrate how the technology can be applied to investigate the role of aluminum in neurological disorders. In Phase II the knowledge and methodology of Phase I will be applied to specific problems of aluminum in neurobiology. It may be possible to evaluate the hypothesis that specific neurological dysfunctions result from attachment of aluminum to specific chemical sites in subcellular structures. Such a capability could lead to developing a means of early diagnosis of one or more of these disorders. Technical bases will be established for commercial aluminum analyses currently beyond the state-of-the-art, and RIS instrumentation will be disseminated to the medical and analytical communities.